I'm not speaking to the qualifications or authority of this first guy, but a lot of what he is saying in the few videos here is pretty good. At the very least, it is better information that is supplied and presumed by video games.Might be useful for RPers, I'm not saying we all need to be experts on real sword fighting, but it is interesting.

Explaining Terminology - Longsword, Greatsword, Shortsword, etc;Swords Vs. Axes - Pros and Cons.Wearing a Sword on the back - Bad idea and why.Strength and Sword Combat - Why it isn't as important as you think.Half-Swording - Grabbing your sword by the blade.Parrying properly.Striking Multiple enemies at once.And a very long one here with two Youtubers discussing Dual Wielding Combat. Of which there isn't (according to them) much historical evidence.

Outside of that particular guy and his charming sidekicks, we have some other videos that are pretty good. Like this one featuring Brian Blessed and an historian fighting expert, made by Creative Assembly to advertise Rome II Total War: Ranged Weapons; throwing, bows, and small-scale siege equipment.

And if we want the professional touch there is Mike Loades, a general historian and medieval weapons enthusiast who did a documentary series about British medieval weapons that is available on Youtube: Mike Loades Documentaries - The one about Longbows is very good.

I just enjoyed watching a few of them, and thought I'd pass the links along.